In still video transceivers capable of transmitting a full quality NTSC (National Television Standards Committee) video frame (for example) over a low bandwidth channel (such as a telephone line), there is a need to store a full quality NTSC video frame in such a manner that individual blocks of the stored data may be rapidly accessed and compressed by a data compression processor, and the resulting compressed data stored in the memory in preparation for transmission over the low bandwidth channel. The amount of uncompressed data stored in the memory, including luminance and two chrominance difference signals, is large. For example, one frame of a high quality luminance signal includes 512 rows of image pixels (each pixel typically comprising an eight bit word) and 512 columns of image pixels.